Peeking through the viewing slots on the wooden observation platform at Étang de la Baie Lucas, we don’t need binoculars to see an embarrassment of wildlife. Large iguanas are nestled in the mangroves, including one bright green female and two males that have turned reddish-orange to display dominance and attract mates. There’s a Brown Pelican on the rocks. In the water, a Snowy Egret looks for food near a Great Egret and Spotted Sandpiper as four White-Cheeked Pintail ducks putter merrily about.

A seasonal fall -- cold and snowy -- in the northern Rockies has enabled Grand Teton National Park in Wyoming to officially move into its winter season with cross-country skiing and snowshoeing.

Each cactus had more personality than the last as we road tripped through Organ Pipe Cactus National Monument in Arizona and admired all the organ pipes, saguaros and senitas. But it was a singular cactus with a striking deformity that stood out.

Winter's vagaries -- blizzards and periods without snow, sub-zero thermometer readings, and unseasonably warm temps -- can toss you curveballs when it comes to enjoying the season in the National Park System, but if you plan carefully you can be prepared with alternatives.